Battery cell and method for producing the same, battery device, electric device, energy storage device

Abstract

The application relates to the field of batteries, and provides a battery monomer, a preparation method of the battery monomer, a battery device, a power utilization device and an energy storage device. The battery monomer comprises: an electrode core assembly, the electrode core assembly is stacked by a positive electrode sheet, a solid-state electrolyte film and a negative electrode sheet or is wound; a shell, the shell has an accommodation space, and the electrode core assembly is located in the accommodation space; the solid-state electrolyte film comprises a core conduction layer, an interface enhancement layer and a mechanical support layer, and the material of the core conduction layer is a metal organic framework material. Based on the MOF composite electrolyte film induced by an electric field and directional growth, a multilayer synergistic design concept is adopted, the accurate combination of a lithium ion conductive MOF film body, an interface enhancement layer and a mechanical support layer is used, and an integrated electrolyte system with high ion conductivity, excellent mechanical properties and interface stability is constructed. The layers are integrated into an overall structure through interface chemical bonding and physical compounding, and function synergy and performance optimization are realized.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a battery cell and its preparation method, a battery device, an electrical device, and an energy storage device. Background Technology

[0002] Metal-organic frameworks (MOFs) have shown great potential in the field of solid-state electrolytes in recent years due to their designable pore structures, high specific surface areas, and tunable chemical compositions. The regular pore structures of MOFs provide ideal channels for ion transport, while their organic-inorganic hybrid properties endow the materials with excellent structural tunability. In particular, lithium-conductive MOFs can achieve high ionic conductivity by introducing lithium-ion carriers or constructing lithium-ion conduction channels within the framework structure. Summary of the Invention

[0003] This application provides a battery cell and its preparation method, a battery device, an electrical device, and an energy storage device, which at least facilitate the achievement of room temperature ionic conductivity >2×10⁻⁶. -3 The combination of S / cm, high voltage stability of 4.5V, and excellent mechanical properties provides an advanced electrolyte material solution for next-generation high-performance solid-state lithium-ion batteries.

[0004] In a first aspect, this application provides a battery cell, comprising:

[0005] A battery cell assembly, wherein the battery cell assembly is formed by stacking or winding a positive electrode sheet, a solid electrolyte membrane, and a negative electrode sheet;

[0006] A housing having a receiving space, within which the battery cell assembly is located;

[0007] The solid electrolyte membrane comprises a core conductive layer, an interface reinforcement layer, and a mechanical support layer, wherein the core conductive layer is made of a metal-organic framework material.

[0008] Optionally, the metal-organic framework material has one-dimensional channels with a diameter of 0.6 nm to 1.2 nm and a pore volume of 0.1 cm³. 3 / g~0.8cm 3 / g, BET specific surface area is 50cm² 2 / g~800cm 2 / g.

[0009] Optionally, the metal-organic framework material includes at least one of the following: a lithium conductive framework with dihydrogen / monohydrophosphate bridging, a derivative of a Zr / Ti-phosphonic acid rigid framework after lithiation, and a multi-anionic metal-phosphonic acid / phosphonate / phosphonic acid-carboxylic acid hybrid framework.

[0010] Optionally, the molecular formula of the lithium conductive framework containing dihydrogen / monohydrophosphate bridging is Li3(H2PO4)(HPO4)2.

[0011] Optionally, the material of the interface reinforcement layer includes a ceramic electrolyte.

[0012] Optionally, the material of the mechanical support layer includes a polymer.

[0013] Secondly, this application provides a method for preparing a battery cell, comprising:

[0014] A battery cell assembly is provided, wherein the battery cell assembly is formed by stacking or winding a positive electrode sheet, a solid electrolyte membrane, and a negative electrode sheet;

[0015] A housing is provided to house the battery cell assembly within the housing;

[0016] Perform the formation step;

[0017] The solid electrolyte membrane comprises a core conductive layer, an interface reinforcement layer, and a mechanical support layer, wherein the core conductive layer is made of a metal-organic framework material.

[0018] Optionally, the preparation method of the metal-organic framework material [taking Li3(H2PO4)(HPO4)2 as an example] includes:

[0019] Preparation of metal-organic framework precursor solutions;

[0020] The metal-organic framework precursor solution was subjected to directional casting under a protective atmosphere at 60°C to 80°C by electric field induction to obtain the metal-organic framework material.

[0021] Optionally, the temperature for the electric field-induced directional casting is 65℃~75℃.

[0022] Optionally, the preparation method of the metal-organic framework precursor solution includes:

[0023] Under an inert atmosphere, the lithium source and coordination component are dissolved in a mixed solvent and mixed to obtain the metal-organic framework precursor solution. The mixed solvent is a mixture of N,N-dimethylformamide and acetonitrile. The total concentration of the lithium source and the coordination component in the metal-organic framework precursor solution is controlled to be 50 mg / mL to 200 mg / mL.

[0024] Optionally, the volume ratio of N,N-dimethylformamide to acetonitrile is 1:1 to 3:1.

[0025] Optionally, in the electric field-induced directional casting, the electric field strength is controlled to increase from the first electric field strength to the second electric field strength within 3h to 6h.

[0026] Optionally, the first electric field strength is 0.05 V / cm to 0.1 V / cm, the second electric field strength is 0.8 V / cm to 10 V / cm, and the rate of increase of the electric field strength is 0.12 (V / cm)·h. -1 ~0.23 (V / cm)·h -1 .

[0027] Optionally, the method for preparing the interface enhancement layer includes:

[0028] The interface enhancement layer is formed by sputtering deposition on the surface of the core conductive layer.

[0029] Optionally, in the sputtering deposition, the working gas pressure is controlled to be 0.1 Pa to 1 Pa, the sputtering power is 100 W to 500 W, the substrate temperature is room temperature to 80 °C, and the deposition rate is 0.05 nm / s to 0.5 nm / s.

[0030] Optionally, the mechanical support layer can be prepared by either solution casting or hot pressing.

[0031] Optionally, the solution casting composite method includes:

[0032] The polymer is dissolved in an organic solvent to form a casting solution;

[0033] After the casting liquid is spread on the surface of the interface reinforcement layer, the organic solvent is evaporated at 80℃~120℃ to obtain the mechanical support layer.

[0034] Optionally, the hot-pressing composite method includes:

[0035] Preparation of polymer preforms;

[0036] The polymer preform is hot-pressed at 60°C to 120°C to obtain the mechanical support layer.

[0037] Thirdly, this application provides a battery device, including a battery cell as described above, or a battery cell obtained by the preparation method described above, wherein the battery device includes one or more of a battery module, a battery pack, and an energy storage battery.

[0038] Fourthly, this application provides an electrical device, which includes a battery device as described above, the battery device being used to provide electrical energy.

[0039] Fifthly, this application provides an energy storage device, which includes the battery device described above, and the battery device is used to store electrical energy. The energy storage device includes a battery pack, and the battery device includes multiple batteries, an energy management system (EMS), a battery management system (BMS), and an energy storage converter (PCS). The electrical devices include vehicles, household appliances, electric motors, medical equipment, scientific instruments, power grids, etc.

[0040] The technical solution provided in this application has at least the following advantages:

[0041] The solid electrolyte membrane in this application adopts a multi-layer synergistic design concept. Through the precise combination of a lithium-ion MOF membrane, an interface reinforcement layer, and a mechanical support layer, an integrated electrolyte system is constructed that simultaneously possesses high ionic conductivity, excellent mechanical properties, and interfacial stability. Each layer forms an integral structure through interfacial chemical bonding and physical composite, achieving functional synergy and performance optimization. The lithium-ion conductive MOF membrane constitutes the core conductive layer of the composite electrolyte, providing a continuous anisotropic channel for lithium-ion transport. This provides an advanced electrolyte material solution for next-generation high-performance solid-state lithium-ion batteries. It facilitates the realization of high-capacity battery cells and is suitable for long-term energy storage applications, such as energy storage systems that can operate continuously for 4 to 8 hours at rated power. Attached Figure Description

[0042] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the drawings in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 The flowchart corresponds to the method for preparing a battery cell provided in the embodiments of this application. Detailed Implementation

[0044] As the background technology shows, the preparation of existing MOF solid electrolytes mainly employs methods such as solvothermal synthesis, room temperature precipitation, or electrochemical deposition. Solvothermal synthesis involves reacting metal salts and organic ligands under high temperature and pressure to generate MOF crystals, which are then used to prepare electrolyte membranes through pressing or solution casting. Room temperature precipitation involves adjusting the solution pH or adding a precipitant to induce MOF crystal precipitation at room temperature. Electrochemical deposition utilizes electrochemical reactions on the electrode surface to control MOF growth. In MOF electrolytes prepared by these methods, the crystal orientation is basically randomly distributed, and ion conduction exhibits isotropic characteristics. The ion conduction mechanism of MOFs mainly relies on their regular pore structure, with lithium ions transported within the pores via a hopping mechanism. For one-dimensional pore MOFs, the conductivity along the pore direction is much higher than that perpendicular to it, but the random orientation prevents this anisotropic advantage from being fully utilized. To improve the overall performance of MOF electrolytes, researchers often employ composite strategies, such as MOF-polymer composites and MOF-ceramic composites. In MOF-polymer composite systems, the polymer provides mechanical support and interfacial wettability, while the MOF provides ion conduction channels. MOF-ceramic composite systems further enhance overall conductivity by introducing inorganic electrolytes with high ionic conductivity. These composite electrolytes work by optimizing performance through the synergistic effect of different components, but the fundamental problem of controlling MOF crystal orientation remains unsolved.

[0045] Current MOF solid-state electrolyte technology faces several key challenges and limitations in practical applications. First, the randomness of MOF crystal orientation is a fundamental obstacle to performance improvement. Randomly oriented MOF crystals cannot form a continuous, efficient ion-conducting network, and numerous grain boundaries and orientation defects severely hinder ion transport, resulting in actual conductivity far lower than theoretical values. Second, most organic ligand MOFs are extremely sensitive to moisture. In battery environments containing trace amounts of moisture, they are prone to degradation reactions such as ligand protonation and metal node hydrolysis, leading to framework structure collapse and loss of ion conductivity. Third, pure MOF materials generally have poor mechanical properties, with insufficient compressive and flexural strength, making it difficult to prepare self-supporting electrolyte membranes with good mechanical integrity. This can easily lead to cracking and pulverization during battery assembly and use. Fourth, MOFs exhibit poor interfacial compatibility with electrode materials, particularly when in contact with lithium metal anodes, easily resulting in side reactions, high interfacial impedance, and poor stability. Fifth, while existing composite strategies can improve the overall performance of MOF electrolytes to some extent, they often come at the cost of sacrificing ionic conductivity, with interfacial impedance between composite components becoming a new performance bottleneck. Sixth, there is a lack of effective techniques for controlling the orientation of MOF crystals. Traditional preparation methods struggle to control the orientation of MOF crystals, and randomly oriented crystals cannot form continuous ion conduction networks. Existing external field induction methods, such as magnetic fields and stress fields, have limited effects on MOF crystals and are highly complex. Finally, the preparation process of MOF electrolytes suffers from poor stability and reproducibility, with significant batch-to-batch performance variations, making it difficult to meet the consistency requirements of industrial production. To address these issues, researchers have proposed various strategies, including MOF composites, interface modification, and structural stabilization, but effective means are still lacking in controlling crystal orientation and constructing anisotropic conduction systems.

[0046] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0047] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0049] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Moreover, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0050] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "part" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0051] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0052] In a first aspect, this application provides a battery cell, comprising:

[0053] A battery cell assembly, wherein the battery cell assembly is formed by stacking or winding a positive electrode sheet, a solid electrolyte membrane, and a negative electrode sheet;

[0054] A housing having a receiving space, within which the battery cell assembly is located;

[0055] The solid electrolyte membrane comprises a core conductive layer, an interface reinforcement layer, and a mechanical support layer, wherein the core conductive layer is made of a metal-organic framework material.

[0056] The solid electrolyte membrane in this application adopts a multi-layer synergistic design concept. Through the precise combination of a lithium-ion MOF membrane, an interface reinforcement layer, and a mechanical support layer, an integrated electrolyte system is constructed that simultaneously possesses high ionic conductivity, excellent mechanical properties, and interfacial stability. Each layer forms an integral structure through interfacial chemical bonding and physical composite, achieving functional synergy and performance optimization. The lithium-ion conductive MOF membrane constitutes the core conductive layer of the composite electrolyte, providing a continuous anisotropic channel for lithium-ion transport. This provides an advanced electrolyte material solution for next-generation high-performance solid-state lithium-ion batteries. It facilitates the realization of high-capacity battery cells and is suitable for long-term energy storage applications, such as energy storage systems that can operate continuously for 4 to 8 hours at rated power.

[0057] Achieved room temperature ionic conductivity >2×10 -3 The combination of S / cm, high voltage stability of 4.5V, and excellent mechanical properties provides an advanced electrolyte material solution for next-generation high-performance solid-state lithium-ion batteries.

[0058] The solid electrolyte membrane of this application is particularly suitable for high-voltage, high-energy-density solid-state lithium-ion battery systems. Regarding the cathode material, it exhibits good interfacial compatibility with high-voltage ternary materials such as NCM811, NCA, and LMNO; regarding the anode material, it can achieve stable matching with lithium metal, silicon-based anodes, and graphite anodes.

[0059] The solid electrolyte membrane operates in a temperature range of -20℃ to 80℃, with an optional range of 0℃ to 60℃, and an even more suitable range of 20℃ to 50℃. Within this temperature range, the composite membrane maintains stable ionic conductivity and mechanical properties.

[0060] In addition to the aforementioned solid electrolyte membrane, the battery cell provided in this application also includes the system integration and process implementation of matching components such as positive and negative electrodes.

[0061] The solid-state lithium-ion battery system is based on the composite electrolyte membrane described in this application, combined with high-performance positive and negative electrode materials and a current collector system. The positive electrode material is a high-voltage, high-capacity layered ternary material, including lithium nickel cobalt manganese oxide (NCM series, NCM523, NCM622, NCM811, etc.), lithium nickel cobalt aluminum oxide (NCA), and high-voltage spinel lithium manganese nickel oxide (LMNO), etc. These materials operate within a voltage range of 4.0V to 5.0V, which matches the electrochemical stability window of the composite electrolyte membrane well.

[0062] The anode material can be selected from various types, including lithium metal, silicon-based materials, and graphite. Lithium metal anodes have the highest theoretical capacity, and can be combined with the composite film of this application to construct a high-energy-density battery system; silicon-based anodes provide high capacity through an alloying mechanism, requiring a composite film to provide good interfacial stability; although graphite anodes have relatively low capacity, they have good cycle stability and are a mature commercial choice.

[0063] The current collector system uses traditional aluminum foil positive electrode current collectors and copper foil negative electrode current collectors, with thicknesses of 10μm~20μm and 6μm~12μm, respectively. The surface of the current collector can be treated with carbon coating or other conductive coatings to improve the adhesion and conductivity with the electrode material.

[0064] Optionally, the metal-organic framework material has one-dimensional channels with a diameter of 0.6 nm to 1.2 nm, specifically 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, 1.0 nm, 1.1 nm, or 1.2 nm, to ensure rapid lithium-ion transport, with a pore volume of 0.1 cm³. 3 / g~0.8cm 3 / g, specifically 0.1cm 3 / g, 0.2cm 3 / g, 0.3cm 3 / g, 0.4cm 3 / g, 0.5cm 3 / g, 0.6cm 3 / g, 0.7cm 3 / g, 0.8cm 3 / g, BET specific surface area is 50cm² 2 / g~800cm 2 / g, specifically 50cm 2 / g、60cm 2 / g, 70cm 2 / g、80cm 2 / g、90cm 2 / g, 100cm 2 / g、200cm 2 / g、300cm 2 / g、400cm 2 / g、500cm 2 / g、600cm 2 / g、700cm 2 / g、800cm 2 / g.

[0065] Optionally, the metal-organic framework material includes at least one of the following: a lithium conductive framework with dihydrogen / monohydrophosphate bridging, a derivative of a Zr / Ti-phosphonic acid rigid framework after lithiation, and a multi-anionic metal-phosphonic acid / phosphonate / phosphonic acid-carboxylic acid hybrid framework.

[0066] Optionally, the molecular formula of the lithium conductive framework containing dihydrogen / monohydrophosphate bridging is Li3(H2PO4)(HPO4)2. The MOF framework contains acidic oxygen sites, including -PO3H groups, -PO2H- groups, phosphonic acid groups, etc. These sites form coordination interactions with lithium ions, providing a favorable jumping path for lithium ion conduction.

[0067] Optionally, the thickness of the interface enhancement layer is 20nm~200nm, specifically 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, or 200nm. An interface enhancement layer that is too thin may not provide sufficient interface protection, while one that is too thick will significantly increase the interface transmission impedance.

[0068] Optionally, the surface roughness Ra of the interface enhancement layer is less than 10 nm, and more preferably less than 5 nm, to ensure close contact with adjacent layers.

[0069] Optionally, the material of the interface reinforcement layer includes a ceramic electrolyte. The interface reinforcement layer of the ceramic electrolyte is located on the surface of the MOF membrane, and its main functions are to improve interface stability, inhibit lithium dendrite growth, and enhance the ionic conductivity of the composite membrane.

[0070] Optionally, the ceramic electrolyte layer is selected from inorganic solid electrolyte materials with high lithium-ion conductivity and electrochemical stability, including garnet-type lithium conductive oxide Li7La3Zr2O. 12 (LLZO), Lithium titanate series Li 1.3 Al 0.3 Ti 1.7 (PO4)3(LATP), lithium zirconate series Li 3.45 Sc 0.95 Si 2.05 O 12 (LLSO), tantalum-doped garnet Li7La3Zr 1.4 Ta 0.6 O 12 (LLZTO), especially LLZO, has an ionic conductivity of up to 10 at room temperature. -4 S / cm~10 -3S / cm, with a wide electrochemical stability window of 0V~6V (vs. Li / Li). + It exhibits good interfacial stability with lithium metal.

[0071] Optionally, the mechanical support layer may be made of a polymer. This can provide mechanical integrity and flexibility to the solid electrolyte membrane, ensuring the structural stability of the electrolyte during battery assembly and use.

[0072] Optionally, the thickness of the mechanical support layer is 5μm to 30μm, specifically 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, or 30μm; the perforation rate of the mechanical support layer is less than 5%, further less than 3%, and preferably less than 1%, to avoid hindering ion conduction; the tensile strength of the mechanical support layer is greater than 50MPa, further greater than 80MPa, and the elongation at break is greater than 100%, further greater than 200%, to meet the mechanical requirements for battery assembly and use.

[0073] Optionally, the polymer needs to possess good mechanical properties and electrochemical stability, including polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyacrylonitrile (PAN), polyimide (PI), polyetheretherketone (PEEK), etc. PVDF or PVDF-HFP can be further used, as they possess excellent electrochemical stability, good mechanical strength, and appropriate flexibility. The mechanical support layer does not introduce electronically conductive fillers, ensuring that the electronic conductivity of the solid electrolyte membrane is ≤1×10⁻⁶. -9 S / cm.

[0074] Secondly, this application provides a method for preparing a battery cell, such as... Figure 1 As shown, it includes:

[0075] S1. Provide a battery cell assembly, wherein the battery cell assembly is formed by stacking or winding a positive electrode sheet, a solid electrolyte membrane and a negative electrode sheet;

[0076] S2. Provide a housing and place the battery cell assembly inside the housing;

[0077] S3. Perform the formation step;

[0078] The solid electrolyte membrane comprises a core conductive layer, an interface reinforcement layer, and a mechanical support layer, wherein the core conductive layer is made of a metal-organic framework material.

[0079] Optionally, the preparation method of the metal-organic framework material [taking Li3(H2PO4)(HPO4)2 as an example] includes:

[0080] Preparation of metal-organic framework precursor solutions;

[0081] The metal-organic framework precursor solution was subjected to directional casting under a protective atmosphere at 60°C to 80°C by electric field induction to obtain the metal-organic framework material.

[0082] Electric field induction technology, as an external field control method, can provide directional driving force during material growth, offering new possibilities for achieving the ordered arrangement of MOF crystals. Furthermore, by combining it with other high-performance electrolyte materials, novel solid-state electrolyte systems with both high ionic conductivity and excellent mechanical properties can be constructed.

[0083] The electric field-induced physical mechanism is based on the synergistic effect of dielectric anisotropy, dipole orientation, and preferred migration of crystal nuclei. MOF precursor molecules align in a gradient electric field, and charged ligand molecules and metal ions preferentially nucleate along the direction of the electric field. As the solvent evaporates and the concentration increases, the crystal nuclei grow and maintain their orientation characteristics, eventually forming MOF films with thickness-oriented anisotropy.

[0084] This application achieves the directional growth and self-assembly of MOF crystals by controlling the preferred orientation of MOF crystals through gradient DC electric field, thus constructing a solid electrolyte system with anisotropic ion conduction characteristics. While significantly improving ion conductivity, it ensures excellent mechanical properties and interface stability, fundamentally solving key technical problems such as discontinuous ion conduction paths, high interface impedance, and insufficient mechanical strength in traditional MOF electrolytes, and providing an advanced electrolyte material solution for high-performance solid-state lithium-ion batteries.

[0085] During the electric field-induced process, the MOF precursor undergoes directional nucleation and growth under the influence of a gradient electric field. Charged ligand molecules and metal ions align in the electric field, forming crystal nuclei with preferred orientation. As the solvent evaporates and the concentration increases, the crystal nuclei grow while maintaining their orientation characteristics, eventually forming an anisotropic MOF film.

[0086] The core innovation of this application lies in the use of gradient electric field to induce the directional growth of Li3(H2PO4)(HPO4)2 phosphate MOF crystals, thereby achieving the preferred orientation of one-dimensional MOF ion channels along the film thickness direction and constructing an anisotropic and efficient ion conduction network.

[0087] The fundamental difference between this technical solution and existing electric field-oriented composite polymer electrolyte (CPE) technology lies in the realization of precise control of MOF crystal orientation and the innovative application of gradient electric field. The high water stability of phosphate-based MOF solves the environmental sensitivity problem of traditional organic ligand MOF. The electric field-induced directional growth technology realizes precise control of MOF crystal orientation. The introduction of LLZO surface layer further improves interface performance and dendrite suppression ability.

[0088] In this application, the key performance characteristics of the solid electrolyte membrane are characterized and controlled through the synergistic threshold relationship between orientation degree and ionic conductivity. The orientation degree (Hermans factor) needs to be above 0.7, further above 0.75, and preferably above 0.8, to ensure the preferred alignment of the one-dimensional channels of the MOF along the membrane thickness direction. The room temperature (25°C) ionic conductivity needs to reach 2 × 10⁻⁶. -3 S / cm or higher, further needs to reach 3×10 -3 S / cm or higher, preferably 5×10 -3 S / cm or higher.

[0089] Orientation degree and ionic conductivity must simultaneously meet the aforementioned threshold requirements to form a synergistic functional constraint. When the orientation degree is below 0.7, even if the ionic conductivity is high, it cannot meet the requirements of this application; when the ionic conductivity is below 2 × 10⁻⁶, it is insufficient. -3 At a ratio of S / cm, even with a high degree of orientation, it still does not meet the requirements of this application. This functional coupling relationship ensures the integrity and effectiveness of the technical solution.

[0090] The orientation factor (Hermans factor) was determined using 2D-WAXS. The complete procedure was as follows: first, the intensity distribution I(φ) of the azimuthal angle of the MOF characteristic diffraction peaks was obtained; then, the distribution was integrated (cosθ). 2 φ), and finally the orientation degree is obtained. Sampling is performed at 3 points (surface / intermediate layer / back side) that span the film thickness, and the mean and coefficient of variation are taken (CV≤20% is acceptable).

[0091] The ionic conductivity σ was determined by electrochemical impedance spectroscopy (EIS) under the following conditions: frequency range 10. 6 Hz~10 -1 Hz, disturbance amplitude 10mV, stainless steel clamp, clamp pressure 0.1MPa~0.5MPa, test temperature (25±1)℃, ambient dew point ≤-40℃ (H2O<50ppm).

[0092] For the determination of interfacial impedance Rint for Li / composite film / stainless steel symmetric cells, the initial interfacial impedance should be less than 50 Ω·cm. 2 Further less than 30 Ω·cm 2Ideally less than 20 Ω·cm 2 .

[0093] The electrochemical stability window was determined by linear sweep voltammetry. The composite membrane needs to have an electrochemical stability window of ≥4.5V at room temperature (vs. Li / Li). + Furthermore, it needs to reach 5.0V or higher, preferably 5.5V or higher.

[0094] Thickness uniformity is characterized by the coefficient of variation of orientation, which should be less than 20%, further less than 15%, and preferably less than 10%. The standard deviation of the thickness of each layer should be less than 10% of the average thickness of each layer, and further less than 5%.

[0095] The thickness of the MOF membrane (referring only to the core conductive layer) is 2μm to 20μm, and in some embodiments it is 5μm to 15μm, or even 8μm to 12μm, to balance ion conduction efficiency and mechanical integrity.

[0096] Optionally, the temperature for the electric field-induced directional casting is 65℃~75℃.

[0097] Optionally, electric field-induced directional casting is performed in a specialized electric field-assisted film-forming device. This device includes a parallel plate electrode system, a time-programmed control system, a temperature control system, and an atmosphere protection system. The parallel plate electrodes are made of stainless steel with a polished surface, and the electrode spacing is adjustable from 0.5mm to 5mm (e.g., 1mm to 3mm). The electrode system is equipped with a high-precision programmable DC power supply, with an adjustable output voltage from 0 to 50V and an adjustable current from 0 to 100mA. The protective atmosphere uses nitrogen or argon, with an oxygen content of less than 10ppm and a moisture content of less than 1ppm. The solvent evaporation rate is controlled by temperature and airflow, with an evaporation time of 2h to 8h (e.g., 3h to 6h).

[0098] Optionally, the preparation method of the metal-organic framework precursor solution includes:

[0099] Under an inert atmosphere, the lithium source and coordination component are dissolved in a mixed solvent and mixed thoroughly to obtain the metal-organic framework precursor solution. The mixed solvent is a mixture of N,N-dimethylformamide and acetonitrile. The total concentration of the lithium source and the coordination component in the metal-organic framework precursor solution is controlled to be between 50 mg / mL and 200 mg / mL, specifically 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL, 100 mg / mL, 110 mg / mL, 120 mg / mL, 130 mg / mL, 140 mg / mL, 150 mg / mL, 160 mg / mL, 170 mg / mL, 180 mg / mL, 190 mg / mL, and 200 mg / mL. The preparation of the metal-organic framework precursor solution is carried out under an inert atmosphere to avoid interference from moisture and oxygen.

[0100] Optionally, the volume ratio of N,N-dimethylformamide to acetonitrile is 1:1 to 3:1, specifically 1:1, 2:1, or 3:1.

[0101] Optionally, in the electric field-induced directional casting, the electric field strength is controlled to increase from the first electric field strength to the second electric field strength within 3h to 6h.

[0102] Optionally, the first electric field strength is 0.05 V / cm to 0.1 V / cm, specifically 0.05 V / cm, 0.06 V / cm, 0.07 V / cm, 0.08 V / cm, 0.09 V / cm, or 0.1 V / cm; the second electric field strength is 0.8 V / cm to 10 V / cm, specifically 0.8 V / cm, 0.9 V / cm, 1 V / cm, 2 V / cm, 3 V / cm, 4 V / cm, 5 V / cm, 6 V / cm, 7 V / cm, 8 V / cm, 9 V / cm, or 10 V / cm; and the rate of increase of the electric field strength is 0.12 (V / cm)·h. -1 ~0.23 (V / cm)·h -1 The programmed pressurization process is carried out simultaneously with solvent evaporation and MOF crystallization, allowing MOFs of different thicknesses to preferentially nucleate and grow under corresponding electric field strengths.

[0103] Optionally, in the electric field-induced directional casting, the current density is ≤0.5mA / cm². 2 This is to ensure that no electrolytic reaction occurs.

[0104] The selection of electric field strength and current density ensures that no detectable electrochemical decomposition occurs in the solvent system. The time-programmed method involves gradually increasing the electric field strength from a low value over time during MOF film preparation, allowing MOF crystals of different thicknesses to grow preferentially under different electric field strengths. The multilayer electrode segmented application method involves setting multiple electrode layers in the film thickness direction and applying different electric field strengths to different layers.

[0105] Optionally, the method for preparing the interface enhancement layer includes:

[0106] The interface enhancement layer is formed by sputtering deposition on the surface of the core conductive layer.

[0107] Optionally, in the sputtering deposition, the working gas pressure is controlled to be 0.1 Pa to 1 Pa, specifically 0.1 Pa, 0.2 Pa, 0.3 Pa, 0.4 Pa, 0.5 Pa, 0.6 Pa, 0.7 Pa, 0.8 Pa, 0.9 Pa, or 1 Pa; the sputtering power is controlled to be 100 W to 500 W, specifically 100 W, 200 W, 300 W, 400 W, or 500 W; and the substrate temperature is controlled to be room temperature to 80°C, specifically 25°C. Temperatures range from 30℃ to 80℃, with deposition rates of 0.05nm / s to 0.5nm / s, specifically 0.05nm / s, 0.1nm / s, 0.15nm / s, 0.2nm / s, 0.25nm / s, 0.3nm / s, 0.35nm / s, 0.4nm / s, 0.45nm / s, and 0.5nm / s.

[0108] In sputtering deposition, magnetron sputtering technology is employed, which allows for precise control of film thickness and composition. Sputtering equipment includes an ultra-high vacuum system (basic vacuum level <10). -6 The equipment includes a sputtering gun (Pa), a magnetron sputtering gun, a target conversion system, and a substrate heating system. For LLZO targets, the purity is above 99.9%, the diameter is 75mm~100mm, and the thickness is 3mm~6mm.

[0109] The substrate temperature must not exceed 80℃ to avoid high-temperature damage to the MOF framework. Pre-sputter cleaning of the target surface takes 3-5 minutes; the actual sputtering time is calculated based on the target thickness and is typically 20-200 minutes.

[0110] The film thickness is monitored in real time during sputtering using a quartz crystal microbalance (QCM) or an optical monitoring system. Sputtering is stopped when the target thickness of 50 nm to 100 nm is reached. The deposited sample is cooled to room temperature in a vacuum to avoid stress cracking caused by rapid temperature changes.

[0111] Optionally, the mechanical support layer can be prepared by either solution casting or hot pressing.

[0112] Optionally, the solution casting composite method includes:

[0113] The polymer is dissolved in an organic solvent to form a casting solution;

[0114] After the casting liquid is spread on the surface of the interface reinforcement layer, the organic solvent is evaporated at 80℃~120℃ to obtain the mechanical support layer, the thickness of which can be controlled by adjusting the gap of the scraper.

[0115] Optionally, the mass fraction of the casting liquid is 15wt%~25wt%.

[0116] Optionally, the hot-pressing composite method includes:

[0117] Preparation of polymer preforms;

[0118] The polymer preform is hot-pressed at 60°C to 120°C to obtain the mechanical support layer.

[0119] Optionally, the pressure of the hot-pressing composite is 1MPa~5MPa.

[0120] During hot pressing, PVDF softens and forms a good bond with the ceramic layer, but the temperature must be strictly controlled to avoid damaging the functional layer prepared in the preceding process.

[0121] The prepared solid electrolyte membrane requires rigorous quality control and performance characterization. Quality control includes visual inspection, thickness measurement, orientation testing, conductivity testing, and interfacial impedance testing.

[0122] Visual inspection ensures the membrane surface is free of defects such as bubbles, cracks, and impurities, and that light transmittance is uniform. Thickness measurement is performed using a high-precision thickness gauge with an accuracy of ±1μm, and multi-point measurements ensure thickness uniformity.

[0123] Orientation was determined using 2D-WAXS testing, with samples taken at different locations on the membrane. The Hermans factor was calculated, and the coefficient of variation (CV) was required to be ≤20%. Conductivity was measured using AC impedance spectroscopy within a frequency range of 10 Hz. 6 Hz-10 -1 Hz, disturbance amplitude 10mV, test temperature 25±1℃, ambient humidity control dew point ≤-40℃.

[0124] Interfacial impedance was tested using a Li / composite film / stainless steel symmetric cell with a clamp pressure of 0.1 MPa to 0.5 MPa, and the initial interfacial impedance Rint was recorded. The electrochemical stability window was determined using linear sweep voltammetry at a scan rate of 1 mV / s and a voltage range of 0–6 V (vs. Li / Li).+ ).

[0125] Solid-state battery assembly using the solid electrolyte membrane of this application is carried out in a dry environment with humidity <1% and dew point <-40℃. The assembly process includes electrode preparation, stacking assembly, and encapsulation.

[0126] The positive electrode is prepared by mixing the positive electrode active material, conductive agent, and binder in a mass ratio of (90~95):(3~6):(2~5) to form an electrode slurry. The slurry is coated onto an aluminum foil current collector and, after drying, compacted to a density of 3.0 g / cm³. 3 ~4.0g / cm 3 The preparation of the negative electrode depends on the type of material and the appropriate process is selected. Lithium metal negative electrodes use lithium metal sheets directly, while silicon-based and graphite negative electrodes require the preparation of corresponding electrodes.

[0127] The stacking assembly is performed in the order of positive electrode / composite electrolyte membrane / negative electrode. The two sides of the composite membrane are in close contact with the positive and negative electrodes respectively, with a contact pressure of 0.1MPa~1MPa. The assembled cells are then placed in aluminum-plastic soft-pack or hard-shell cases and vacuum-sealed.

[0128] Battery performance testing includes charge-discharge cycles, rate performance, temperature characteristics, and safety performance. Charge and discharge are performed in constant current / constant voltage mode with a current density of 0.1 mA / cm². 2 ~5mA / cm 2 The voltage range is determined based on the cathode material. Cycle stability testing should be performed for at least 100 cycles, recording changes in capacity retention and coulombic efficiency.

[0129] To meet the demands of large-scale production, the process described in this application can be developed into a continuous production model. Electric field-induced casting can be modified into a roll-to-roll continuous process, equipped with closed-loop control of field strength / temperature / wind speed and an online 2D-XRD orientation monitoring system to achieve real-time quality control. Magnetron sputtering can utilize a large-area sputtering system, allowing multiple targets to work simultaneously, thus improving production efficiency.

[0130] The key to continuous production lies in maintaining the consistency of process parameters, especially the distribution of electric field intensity, uniformity of temperature field, and sputtering uniformity. Through precise process control and online monitoring, a high degree of consistency in performance between batches can be achieved.

[0131] Thirdly, this application provides a battery device, including a battery cell as described above, or a battery cell obtained by the preparation method described above, wherein the battery device includes one or more of a battery module, a battery pack, and an energy storage battery.

[0132] Fourthly, this application provides an electrical device, which includes a battery device as described above, the battery device being used to provide electrical energy.

[0133] Fifthly, this application provides an energy storage device, which includes the battery device described above, and the battery device is used to store electrical energy. The energy storage device includes a battery pack, and the battery device includes multiple batteries, an energy management system (EMS), a battery management system (BMS), and an energy storage converter (PCS). The electrical devices include vehicles, household appliances, electric motors, medical equipment, scientific instruments, power grids, etc.

[0134] The innovations of this application compared to existing technologies are also reflected in the following aspects.

[0135] (a) Technological innovation in electric field-induced directional growth

[0136] Existing methods for preparing MOF solid electrolytes mainly employ traditional solvothermal synthesis, room temperature precipitation, or simple solution casting. The crystal orientation of MOF electrolytes prepared by these methods is randomly distributed, and the ion conduction exhibits isotropic characteristics, which cannot fully utilize the conduction advantages of one-dimensional ion channels in MOF materials.

[0137] This application provides a gradient DC electric field-induced directional growth technique. By applying a time-programmed E(t) or segmented multilayer electrode, an equivalent gradient electric field (0.05V / cm~10V / cm) is formed along the film thickness direction, actively controlling the nucleation and growth process of MOF crystals. This achieves the preferred orientation of one-dimensional ion channels along the film thickness direction, constructing an anisotropic and highly efficient ion conduction network. This technological breakthrough from "random orientation" to "directional orientation" provides a completely new path for improving the performance of MOF electrolytes.

[0138] (b) Scientific selection and innovation of material systems

[0139] Traditional MOF solid electrolytes mostly use organic ligand-based MOF materials. These materials generally suffer from problems such as sensitivity to moisture, easy degradation in the battery environment, and poor water stability, which seriously restricts their practical application.

[0140] This application selects a phosphoric acid / phosphonic acid-anchored lithium-ion conductive MOF material as the matrix framework. This material possesses one-dimensional lithium-ion conduction channels (pore size 0.6 nm~1.2 nm), acidic oxygen sites coordinated and fixed within the framework, and excellent water stability, fundamentally solving the environmental sensitivity problem of traditional organic ligand MOFs. The phosphoric acid / phosphonic acid groups form strong coordination bonds with the metal nodes, providing excellent chemical and electrochemical stability.

[0141] (c) Innovative protection strategies for functional synergy thresholds

[0142] The performance evaluation of existing technologies is mainly based on single indicators such as ionic conductivity or mechanical strength, lacking a comprehensive performance evaluation standard, and making it difficult to establish an accurate structure-performance correlation.

[0143] This application establishes a system with "orientation degree ≥ 0.7 and room temperature ionic conductivity ≥ 2 × 10⁻⁶". -3 The functional synergy threshold relationship of "S / cm" ensures the integrity and effectiveness of the technical solution. Only technical solutions that simultaneously meet the dual thresholds of orientation and conductivity fall within the scope of this application.

[0144] (d) System design innovation of multi-layered collaborative structure

[0145] Existing MOF electrolyte modification mainly adopts a single strategy, such as simple MOF-polymer physical composite or MOF-ceramic mechanical mixing. These methods are difficult to fully realize the functions of each component and often have problems such as high interfacial impedance and poor binding force.

[0146] This application designs a multi-layered synergistic structure consisting of a directional MOF membrane, an LLZO ceramic interface layer (50-100nm), and a PVDF mechanical support layer, achieving functional division and synergistic optimization: the MOF layer provides anisotropic ion conduction channels, the LLZO layer provides interface stability and dendrite suppression, and the PVDF layer provides mechanical support and flexibility. The three layers are bonded together at the interface to form an integrated composite membrane.

[0147] (e) Technological breakthroughs in process temperature control

[0148] Traditional MOF composite electrolyte preparation often requires high-temperature treatment, which can easily damage the MOF framework structure and affect ion conduction performance. Existing composite processes lack protective measures for temperature-sensitive components.

[0149] This application ensures the structural integrity of the MOF framework throughout the entire fabrication process through strict temperature control (sputtering ≤80℃, composite ≤120℃) and a stepwise preparation strategy. The magnetron sputtering substrate temperature is strictly controlled below 80℃, and the polymer composite process employs a milder method primarily based on solution casting, avoiding high-temperature damage.

[0150] (f) Safety design innovations for electronic insulation

[0151] Existing composite electrolytes often neglect electronic insulation requirements while improving ion conduction, which may introduce electronically conductive components that could lead to self-discharge or short-circuit risks.

[0152] This application explicitly specifies that the electronic conductivity of the composite film is ≤1×10⁻⁶. -9 With a S / cm ratio, the polymer support layer does not introduce electronically conductive fillers, ensuring the intrinsic insulating properties of the electrolyte. This safety design philosophy guarantees the long-term stability and safety of solid-state batteries.

[0153] (g) Establishment and innovation of standardized testing methods

[0154] The lack of unified standards for orientation and interface performance testing in existing technologies makes it difficult to compare different studies, which affects technological development and industrialization.

[0155] This application establishes a standardized testing methodology: orientation is measured using 2D-WAXS at three sampling points across the film thickness; ionic conductivity is measured using EIS under strictly controlled environmental conditions (25±1℃, dew point ≤-40℃); and interfacial impedance is evaluated using a Li / composite film / stainless steel symmetric cell. These standardized methods provide a reliable basis for technical evaluation and quality control.

[0156] (h) Engineering innovation in continuous production

[0157] Current MOF electrolyte preparation methods are mainly small-batch laboratory preparations, lacking process design and quality control systems for large-scale production, which restricts industrial application.

[0158] This application provides a complete technical solution suitable for continuous production, including roll-to-roll electric field-induced casting, large-area magnetron sputtering, closed-loop control of field strength / temperature / wind speed, and an online 2D-XRD orientation monitoring system. This engineering design lays the technical foundation for the large-scale production of MOF solid electrolytes.

[0159] To verify the impact of the electric field-induced directional growth technology proposed in this application on the performance of MOF composite solid electrolytes, this application designed a series of embodiments and comparative examples to systematically explore the effects of key technical elements such as the selection of phosphate-based lithium conductive MOF materials, gradient electric field-induced directional growth process, LLZO ceramic interface reinforcement layer, and PVDF mechanical support layer on the ionic conductivity, anisotropic conduction characteristics, interface stability, and battery cycle performance of the composite electrolyte (as shown in Tables 1-1 and 1-2). The following details the material selection, composite electrolyte membrane preparation, battery assembly, and performance testing methods.

[0160] The materials used in the following embodiments and comparative examples are as follows:

[0161] MOF precursor materials:

[0162] The preparation of the phosphate-based lithium conductive MOF [Li-HPPO, Li3(H3PO4)(HPO4)2] used lithium phosphate (Li3PO4, purity ≥99%) and phosphoric acid (H3PO4, 85wt% aqueous solution) as the phosphorus and lithium sources, respectively, and dodecyltrimethylammonium bromide (DTAB), purity ≥99%, as the structure directing agent. The ZIF-8 lithiation derivative used in Comparative Example 5 used zinc nitrate [Zn(NO3)2·6H2O] and 2-methylimidazole as precursors, and the lithiation treatment was performed using a methanol solution of lithium chloride (LiCl). The Zr-phosphonate lithiation framework used in Example 13 used zirconium tetrachloride (ZrCl4) and 1-hydroxyethoxy-1,1-diphosphonic acid (HEDP) as precursors, and was lithiated with a lithium hydroxide solution.

[0163] Solvent system:

[0164] The MOF precursor solution was prepared using a mixed solvent of N,N-dimethylformamide (DMF, anhydrous grade, water content <50ppm) and acetonitrile (ACN, anhydrous grade, water content <20ppm). The volume ratio of the two solvents was adjusted within the range of 1:1 to 3:1 according to the experimental design, and 2:1 was selected.

[0165] Ceramic interface layer materials:

[0166] The LLZO target has a purity of ≥99.9%, a diameter of 75 mm, and a thickness of 5 mm, and is used for magnetron sputtering deposition. The LLZTO target used in Example 14 has the same specifications.

[0167] Polymer support layer material

[0168] Polyvinylidene fluoride (PVDF, M w =500000g / mol~600000g / mol, battery grade), solvent used is N-methylpyrrolidone (NMP, anhydrous grade).

[0169] Battery materials:

[0170] The positive electrode uses NCM811 (LiNi) 0.8 Co 0.1 Mn 0.1 O2) was used as the active material. In Example 15, LMNO (LiNi) was used. 0.5 Mn 1.5 O4) High-voltage positive electrode. The negative electrode uses a 50μm thick lithium metal foil. The positive electrode slurry formulation by mass ratio is: 92% active material, 4% conductive carbon black Super P, 1% carbon nanotubes (CNTs), and 3% PVDF binder. The surface density of the positive electrode is controlled at (20±0.5) mg / cm³. 2 The compacted density is 3.3 g / cm³. 3 .

[0171] All the chemical reagents mentioned above are analytical grade or battery-grade materials, available commercially, and require necessary purification or drying before use. All operations involving water- and oxygen-sensitive materials were performed in an argon-atmospheric glove box, where the water and oxygen content was controlled below 0.1 ppm.

[0172] Preparation of MOF composite electrolyte membrane:

[0173] According to the stoichiometric ratio of Li3(H2PO4)(HPO4)2, Li3PO4 and H3PO4 were accurately weighed, and an appropriate amount of DTAB structure-directing agent (3wt% of the total precursor mass) was added and dissolved in a DMF / ACN mixed solvent. Taking Example 1 as an example, the total precursor concentration was controlled at 120 mg / mL, and the solvent volume ratio DMF:ACN = 2:1. The solution was magnetically stirred at 40°C for 2 h until completely dissolved, and then filtered through a 0.45 μm PTFE filter membrane to remove insoluble matter, obtaining a clear and transparent precursor solution. The entire solution preparation process was carried out under an argon atmosphere.

[0174] In Comparative Example 5, the precursor solution of the ZIF-8 lithiation derivative was prepared at the same concentration, using Zn(NO3)2·6H2O and 2-methylimidazole as raw materials dissolved in a methanol / DMF mixed solvent. In Comparative Example 7, pre-synthesized Li-HPPO powder (hydrothermal synthesis, 200℃ / 24h, particle size D50 approximately 500nm) was dispersed in the same DMF / ACN mixed solvent to form a suspension.

[0175] The prepared precursor solution was uniformly coated onto the surface of a stainless steel substrate electrode using a scraping method. The scraper gap was set according to the target MOF film thickness (in Example 1, the gap was set to 120 μm). After coating, the gradient electric field induction program was immediately started. Electric field-induced directional casting was performed in a dedicated parallel plate electrode system, which included stainless steel parallel plate electrodes (surface polished, electrode spacing 10 mm), a high-precision programmable DC power supply (output voltage adjustable from 0 to 50 V, current adjustable from 0 to 100 mA), a temperature control system (accuracy ±2 °C), and an inert atmosphere protection system (Ar, O2 < 10 ppm, H2O < 1 ppm).

[0176] The gradient electric field was achieved through time-programmed E(t). Taking Example 1 as an example, the electric field strength linearly increased from 0.1 V / cm to 0.8 V / cm during MOF crystallization, with the voltage increase rate synchronized with solvent evaporation and MOF crystallization, and the total voltage increase time being 3-5 hours. The current density was monitored throughout and strictly controlled at 0.5 mA / cm. 2The following ensures that no detectable electrochemical decomposition occurs in the solvent system. The casting process is carried out at a controlled temperature; in Example 1, the temperature is set at 70°C and achieved through a hot plate heating system. Solvent evaporation occurs simultaneously under the action of an electric field, with an evaporation time of 4-6 hours. Throughout the process, the MOF precursor undergoes directional nucleation and preferential growth under the action of a gradient electric field. Charged ligand molecules and metal ions align along the direction of the electric field. As the solvent evaporates and its concentration increases, the crystal nuclei grow and maintain their orientation characteristics, ultimately forming a MOF film with an anisotropic structure in the thickness direction.

[0177] Example 2 employs a multi-layer electrode segmented application method to achieve a gradient electric field. By setting three segmented electrodes along the film thickness direction, different electric field intensities are applied to different layers (0.1 V / cm for the bottom layer, 0.4 V / cm for the middle layer, and 0.8 V / cm for the top layer), verifying the equivalence of the gradient implementation method. Comparative Example 1 does not apply an electric field; all other preparation conditions are completely consistent with Example 1. Comparative Example 2 applies a constant electric field of 0.4 V / cm, with no gradient change. Comparative Example 7 uses a pre-prepared Li-HPPO powder suspension for casting, applying the same gradient electric field as Example 1, but without the in-situ crystallization process. Specific process parameters for each example and comparative example are detailed in the experimental design summary table.

[0178] After the directional MOF film was prepared, an LLZO ceramic interface layer was deposited on the film surface using magnetron sputtering. The sputtering equipment included an ultra-high vacuum system (basic vacuum level <10). -6 The sputtering parameters were controlled as follows: working pressure 0.5 Pa (Ar), sputtering power 200 W, substrate temperature ≤ 60 °C (to avoid high-temperature damage to the MOF framework), and deposition rate approximately 0.1 nm / s. Pre-sputtering cleaning of the target surface for 5 min was performed before formal deposition began. Taking Example 1 as an example, the deposition time was approximately 700 s, stopping when the target thickness of 70 nm was reached. The deposited sample was allowed to cool naturally to room temperature in a vacuum. Comparative Example 4 did not undergo LLZO sputtering and proceeded directly to the next polymer composite process. Example 14 used an LLZTO target instead of LLZO, while maintaining the same sputtering parameters.

[0179] Composite of PVDF polymer mechanical support layer:

[0180] PVDF was dissolved in NMP to form a homogeneous solution of 18 wt%, and magnetically stirred at 60°C for 4 hours until completely dissolved. The PVDF solution was uniformly coated onto the LLZO side of the MOF / LLZO composite membrane, with the doctor blade gap set according to the target support layer thickness (80 μm in Example 1). After coating, the membrane was dried in a vacuum oven at 80°C for 6 hours, followed by drying at 120°C for another 2 hours to ensure complete removal of NMP. After cooling, the membrane was peeled off from the substrate electrode to obtain a self-supporting MOF / LLZO / PVDF three-layer composite electrolyte membrane. In Example 1, the final total thickness of the composite membrane was approximately 98 μm (MOF layer 10 μm + LLZO layer 70 nm + PVDF layer 18 μm, where the LLZO layer thickness was negligible). In Comparative Example 6, the MOF / LLZO bilayer membrane was used directly as the electrolyte without a PVDF support layer.

[0181] Battery assembly:

[0182] In this application, the full-cell test uses a CR2032 coin cell structure. The composite electrolyte membrane is cut into 16mm diameter discs, with the LLZO side facing the lithium metal anode side. The cathode is cut into 12mm diameter discs, with an active material area of ​​approximately 1.13cm². 2 The positive electrode, composite electrolyte membrane, and lithium metal negative electrode (15.6 mm in diameter and 50 μm in thickness) were stacked sequentially, and appropriate pressure was applied using stainless steel gaskets and spring sheets. The coin cell was assembled in a glove box. To improve solid-state interface contact, a trace amount (~2 μL) of ionic liquid was added between the electrode and the electrolyte membrane as an interface wetting agent. The charge / discharge voltage window for the NCM811 positive electrode system was 2.8 V to 4.3 V, and for the LMNO positive electrode system (Example 15), it was 3.5 V to 4.9 V. Formation employed a low-current stepped charging strategy, charging to the upper voltage limit at 0.05 C in the first cycle, followed by three cycles of 0.1 C charge / discharge for activation.

[0183] To systematically evaluate the performance of the composite solid electrolyte of this application and verify the effectiveness of the various technological innovations, the following uniform performance tests were performed on all embodiments and comparative examples in the experimental design table. All data are based on the average value of tests on three parallel samples.

[0184] (1) Ionic conductivity test in the film thickness direction (T1)

[0185] The thickness-plane ionic conductivity of the composite electrolyte membrane was determined by electrochemical impedance spectroscopy (EIS) at 25 °C. The electrolyte membrane was sandwiched between two stainless steel (SS) blocking electrodes with an electrode area of ​​2.01 cm². 2The clamp pressure was 0.3 MPa, and impedance testing was conducted within a frequency range of 0.1 Hz to 1 MHz, with an AC disturbance amplitude of 10 mV. The tests were performed in a dry environment with a dew point ≤ -40℃ (H2O < 50 ppm). The bulk ionic conductivity was calculated using the formula σ⊥ = L / (R × S), where L is the total film thickness (μm), R is the bulk resistance corresponding to the high-frequency intercept (Ω), and S is the effective electrode area (cm²). 2 σ⊥ is a core parameter for measuring the ion conductivity of electrolytes. It directly reflects whether electric field-induced directional growth has successfully constructed a through-type ion conduction channel in the thickness direction, and is also the threshold for determining synergy: σ≥2×10⁻⁶. -3 The key criterion for whether S / cm is satisfied.

[0186] (2) Anisotropy ratio test (T2)

[0187] The in-plane ionic conductivity σ∥ of the electrolyte membrane was determined at 25℃ using an in-plane electrode configuration. The electrolyte membrane was placed flat between two parallel stainless steel electrodes (electrode spacing 5 mm, electrode width 10 mm), and EIS testing was performed in the frequency range of 0.1 Hz to 1 MHz. σ∥ was calculated using the formula σ∥ = d / (R × w × L), where d is the electrode spacing, w is the electrode width, and L is the membrane thickness. The anisotropy ratio A = σ⊥ / σ∥, this index can functionally prove the existence of oriented structures through electrochemical methods without relying on structural characterization methods. When A is significantly greater than 1, it indicates that the ion conduction channels in the thickness direction are preferentially oriented compared to the in-plane direction, that is, the one-dimensional channels of the MOF have been preferentially oriented along the thickness direction. For samples without electric field induction or pre-dispersed powder orientation, the A value is usually close to 1.

[0188] (3) Initial interface impedance test (T3)

[0189] Li / film / Li symmetric cells were assembled at 25℃, and EIS tests were performed in the frequency range of 0.1Hz to 1MHz. During testing, the LLZO surface was consistently oriented towards the Li side to ensure consistent interface configuration across groups, thus enabling univariate comparisons. The initial interface impedance Rint was taken as the diameter of the high-frequency semicircle in the Nyquist plot, in Ω·cm. 2 Rint directly reflects the interfacial contact quality and charge transfer characteristics between the electrolyte and the lithium metal anode, and is a core indicator for evaluating the contribution of the LLZO interface reinforcement layer to reducing interfacial impedance.

[0190] (4) Electrochemical stability window test (T4)

[0191] The electrochemical stability window of the electrolyte membrane was determined using linear sweep voltammetry (LSV) at 25 °C. A Li / membrane / SS asymmetric cell was assembled, and the open-circuit voltage was scanned to 6.0 V (vs. Li / Li) at a scan rate of 0.5 mV / s.+ The recorded oxidative decomposition current density reached 1 μA / cm. 2 The voltage value at that time is taken as the oxidation decomposition potential Eox. The electrochemical stability window is the upper limit of the voltage range in which the electrolyte can operate stably. Eox ≥ 4.5V is the key evidence for the high voltage stability claimed in this application, and also the preliminary verification to support the suitability of Example 15 (LMNO ~ 4.7V cathode).

[0192] (5) Constant current polarization stability test of Li symmetric cell (T5)

[0193] At 25°C, a Li / film / Li symmetric cell was assembled, with an output of 0.1 mA / cm². 2 Constant current charge-discharge cycle tests were conducted at current density, with each half-cycle lasting 1 hour. Cycling continued until abnormal fluctuations in the polarization voltage occurred (defined as a sudden increase in overpotential >50% or the appearance of irregular oscillations). The cumulative stabilization time tstable (h) and the average overpotential Δη (mV) during the cycle were recorded. This test is used to evaluate the interfacial compatibility between the electrolyte and the lithium metal anode, as well as its ability to suppress lithium dendrite growth. It is a key test comprehensively reflecting the synergistic effect of LLZO interface enhancement, uniform deposition of orientation structure, and PVDF mechanical suppression.

[0194] (6) Tensile property test (T6)

[0195] At 25℃, the electrolyte membrane was cut into standard dumbbell-shaped strips (referring to GB / T1040 standard) and tested on a universal testing machine at a tensile rate of 5 mm / min. Tensile strength (MPa) and elongation at break (%) were recorded. Five parallel samples were tested for each sample, and the average value was taken. Mechanical properties are important indicators for the practical application of solid-state electrolytes. Good mechanical strength can maintain the integrity of the membrane under battery assembly pressure while inhibiting lithium dendrite penetration, while moderate flexibility is beneficial for adapting to electrode volume changes and industrial winding / stacking processes.

[0196] (7) Electronic conductivity test (T7)

[0197] The electronic conductivity σ of the electrolyte membrane was determined using the DC polarization method at 25℃. e Assemble the SS / membrane / SS cell, apply a 0.5V DC voltage, and record the current change over time until steady state (typically 2h~4h). Calculate σ using the steady-state current. e =I ss ×L / (V×S). Electronic conductivity is a safety indicator to ensure the intrinsic insulating properties of the electrolyte, σ e ≤1×10 -9S / cm is a clearly defined technical requirement in this application. This test eliminates false high ionic conductivity signals that may be caused by mixed conductivity, and has particular defensive value for Comparative Example 4 (the absence of an LLZO layer may lead to increased electron leakage) and Comparative Example 5 (the electronic insulation of the organic ligand MOF system is unknown).

[0198] (8) Full battery cycle capacity retention test (T8)

[0199] NCM811 / film / Li coin cells (using LMNO cathode in Example 15) were assembled at 25°C and cycle performance tests were performed. The charging regime was 0.5C constant current charging to the upper voltage limit (4.3V for NCM811 system, 4.9V for LMNO system), followed by constant voltage charging to the current cutoff at 0.05C. The discharging regime was 0.5C constant current discharging to the lower voltage limit (2.8V for NCM811 system, 3.5V for LMNO system). The discharge capacity was recorded after the 200th cycle, and the capacity retention rate was calculated as (200th cycle discharge capacity / initial discharge capacity) × 100%. The cycle capacity retention rate is the comprehensive performance indicator resulting from all structural optimizations and material selections.

[0200] (9) Rate discharge performance test (T9)

[0201] At 25℃, with a fixed charging rate of 0.2C (constant current and constant voltage charging to the upper voltage limit, cutoff at 0.05C), discharge rates were set to 0.2C, 0.5C, 1C, and 2C, with 5 cycles at each rate. The capacity retention at 2C was calculated using the 0.2C discharge capacity as a baseline (100%). Rate performance reflects the battery's fast charging and discharging capability. Samples with high orientation should exhibit a more significant advantage at high rates because through-type ion conduction channels can effectively reduce concentration polarization under high current density.

[0202] Through the above-described systematic experimental design and standardized preparation process, the contribution of the various technological innovations of this application to the performance of MOF composite solid electrolyte can be accurately evaluated, providing a reliable experimental basis for the application of electric field-induced directional growth technology in the field of solid-state batteries.

[0203] Test item allocation instructions:

[0204] The core innovation verification group (Examples 1 and Comparative Examples 1-7) performed all 9 tests (T1-T9) to fully evaluate the necessity and contribution of each core innovation. The process parameter window verification group (Examples 2-11) performed the first 3 tests (T1-T3: ionic conductivity, anisotropy ratio, and interfacial impedance) to efficiently obtain parameter change trends. The application expansion and synergistic optimization group (Examples 12-15) selectively performed tests according to their respective verification objectives: Example 12 (multi-parameter synergistic optimization) performed 7 tests (T1-T5 and T8-T9); Example 13 (replacing MOF materials) performed 3 tests (T1-T2 and T4); Example 14 (replacing ceramic layers) performed 3 tests (T1, T3, and T5); and Example 15 (high-voltage cathode) performed 4 tests (T1, T4, T8, and T9).

[0205] The experimental results are shown in Tables 2-1 and 2-2, which fully demonstrate the key role of electric field-induced directional growth technology in improving the ion conductivity of MOF composite solid electrolytes. The room-temperature thickness-direction ion conductivity of Example 1 reached 3.2 × 10⁻⁶. -3 S / cm, compared to Comparative Example 1 without an applied electric field (3.5 × 10⁻⁶ S / cm), -4 The S / cm ratio was improved by approximately 9 times. This order-of-magnitude improvement directly verifies the core design concept of this application, which involves inducing the preferential orientation of one-dimensional ion channels in MOFs along the thickness direction using a gradient electric field to construct a through-type conduction network. More importantly, the anisotropy ratio data provides functional evidence for the existence of the oriented structure: the A value of Example 1 reaches 3.5, indicating that the conductivity in the thickness direction is 3.5 times that in the in-plane direction, while the A value of Comparative Example 1 is only 1.1, which is close to isotropy. This intuitively shows that the MOF crystal exhibits a random orientation distribution under no-electric-field conditions, and the advantages of one-dimensional channels cannot be utilized.

[0206] The results of Comparative Example 7 (orientation of pre-fabricated Li-HPPO powder during casting under an electric field) further support the irreplaceable technical position of "in-situ directional growth" from a mechanistic perspective. The σ⊥ of Comparative Example 7 is 5.5 × 10⁻⁶. -4 The S / cm and A value of only 1.3, while slightly better than Comparative Example 1 (without any electric field), are far inferior to Example 1. This comparison rules out the possibility of achieving high performance simply by arranging pre-fabricated MOF powders in a row using an electric field. The interfacial contact between pre-fabricated powder particles is essentially a physical contact rather than a chemical continuity. The grain boundaries and voids between grains block the passage of ion conduction channels. Even if the electric field causes the particles to exhibit a certain orientation, it is impossible to form the chemically continuous fast ion channels established through the in-situ crystallization process in Example 1. This result fundamentally proves the core value of the "electric field-induced in-situ directional growth" technical solution of this application.

[0207] Comparative Example 2 was treated with a constant electric field of 0.4 V / cm, and its σ⊥ was 1.2 × 10⁻⁶.-3 The conductivity (S / cm) and A value (A) are 1.8. Although this represents a significant improvement compared to Example 1 without an electric field (conductivity increased by approximately 3.4 times), it is still significantly lower than Example 1 using a gradient electric field (conductivity differs by approximately 2.7 times, and A value differs by approximately 1.9 times). This difference reveals the fundamental difference between gradient electric fields and constant electric fields in the MOF crystal orientation control mechanism. Under a constant electric field, all thicknesses of the film experience the same electric field intensity. The region at the bottom that crystallizes first may form a local orientation structure, but as the solvent evaporates, the coupling changes in the upper layer concentration gradient and the electric field environment lead to uneven orientation degrees in different thickness regions. In contrast, a gradient electric field, through time-programmed E(t), ensures that each thickness layer of the film experiences an appropriate field intensity drive within its critical crystallization time window, achieving a uniform distribution of orientation from the bottom to the surface.

[0208] Comparative Example 3 (weak gradient electric field 0.05 V / cm → 0.2 V / cm) further verifies the threshold effect of the electric field driving force. The σ⊥ of Comparative Example 3 is 7.5 × 10⁻⁶. -4 S / cm and A value of 1.5 indicate that some degree of orientation has indeed occurred, but they are far from reaching the cooperation thresholds claimed in this application—orientation degree ≥ 0.7 and σ⊥ ≥ 2 × 10⁻⁶. -3 The S / cm requirement must be met simultaneously. When the final value of the electric field gradient is too low, the orientation driving force for the MOF nucleus is insufficient to overcome the randomization effect of thermal motion, resulting in the crystal only forming a partial orientation and failing to establish a continuous ion channel network that completely penetrates the film thickness. The combined data from Comparative Examples 2 and 3 show that not only is the presence of an electric field required, but it also needs to be applied in a gradient manner with a sufficient field strength (final value ≥ 0.5 V / cm) to achieve the highly oriented structure sought in this application.

[0209] The test results of Comparative Example 4 (without the LLZO interface layer) clearly demonstrate the indispensable interface protection function of the LLZO ceramic interface layer in the composite electrolyte system. Comparative Example 4 retains the complete gradient electric field-induced oriented MOF film and PVDF support layer, with σ⊥(2.8×10⁻⁶). -3 The S / cm and A values ​​(3.3) are close to those of Example 1, indicating that the LLZO layer has a limited direct contribution to bulk orientation and ion conduction. However, the initial interfacial impedance Rint of Comparative Example 4 increases sharply to 125 Ω·cm. 2 This is Example 1 (25Ω·cm) 2 The stability time of the Li-symmetric cell was only 80 hours, less than one-sixth of that of Example 1 (>500 hours). This characteristic mode of "decent bulk performance but rapid interface deterioration" reveals that the direct contact between the MOF material and lithium metal in the absence of an LLZO protective layer triggered continuous interfacial side reactions.

[0210] Further analysis revealed that the electronic conductivity σ of Comparative Example 4... e 2.5×10 -9 S / cm, although still within the insulation range, is lower than that of Example 1 (5.0 × 10). -10 The S / cm ratio is approximately 5 times higher, suggesting the possible presence of trace amounts of electronically conductive byproducts at the MOF / Li direct interface. The electrochemical stability window (Eox) of Comparative Example 4 also decreased to 4.2V, lower than the 4.8V of Example 1, indicating that the composite film lacking the LLZO layer cannot meet the technical requirement of high voltage stability ≥4.5V. Comparative Example 4 exhibited a capacity retention of only 72.0% after 200 cycles, one of the lowest values ​​among all core validation group samples, confirming the fatal impact of interfacial instability on the long-term reliability of the battery. In summary, the LLZO ceramic interfacial layer, by constructing a chemically inert and ionically conductive protective barrier between the MOF film and lithium metal, effectively suppresses interfacial side reactions and lithium dendrite growth, making it a necessary technical element for achieving long-term stable operation of the electrolyte.

[0211] Comparative Example 5 used a ZIF-8 lithium derivative instead of the Li-HPPO phosphate-based MOF, with all other conditions identical to Example 1, to verify the rationality of the material system selection. The σ⊥ of Comparative Example 5 was only 4.5 × 10⁻⁶. -4 The S / cm ratio is much lower than that of Example 1, and the electrochemical stability window Eox drops to 3.8V, which cannot meet the high voltage matching requirement of ≥4.5V. The stability of the organic imidazole ligand of ZIF-8 in the electrochemical environment is significantly weaker than that of the phosphoric acid / phosphonic acid inorganic anchoring structure of Li-HPPO, which provides excellent chemical and water stability through the strong coordination bond between the phosphate group and the metal node.

[0212] Electronic conductivity σ of Comparative Example 5 e Increased to 3.5 × 10 -9 The S / cm value suggests that the organic ligand MOF may undergo partial decomposition and generate conductive byproducts in an electrochemical environment. The capacity retention of only 68.0% after 200 cycles and the 2C rate retention of 48.0% are the lowest among all samples, further confirming the insufficient long-term stability of the organic ligand MOF system under actual battery operating conditions. These data strongly support the technical decision of selecting phosphoric acid / phosphonic acid anchored MOFs in this application—not only achieving higher intrinsic ionic conductivity but also ensuring structural and performance stability under wide voltage windows and long-term cycling conditions.

[0213] The mechanical properties of Comparative Example 6 (without the PVDF support layer) most clearly demonstrate the irreplaceable nature of the support layer. The tensile strength of Comparative Example 6 drops sharply to 1.8 MPa, and the elongation at break is only 0.5%, which are 14% and 3% of Example 1 (12.5 MPa, 15.2%), respectively. This brittle material characteristic means that the pure MOF / LLZO bilayer film is extremely prone to cracking when the battery is stacked during assembly, and cannot adapt to the volume changes of the electrodes during charging and discharging.

[0214] It is worth noting that the bulk ionic conductivity of Comparative Example 6 (σ⊥=3.5×10⁻⁶) -3 The S / cm ratio and anisotropy ratio (A=3.5) are almost identical to those of Example 1, and the Rint is only 28 Ω·cm. 2 This indicates that the PVDF layer itself has no negative impact on the intrinsic conductivity of the electrolyte. However, the Li symmetric battery in Comparative Example 6 had a stable time of only 100 hours and a capacity retention rate of 62.0% after 200 cycles, both significantly worse than Example 1. This pattern of "decent electrochemical performance but drastically deteriorated actual battery performance" clearly shows that, in the absence of mechanical support, microcracks and defects generated in the electrolyte membrane during repeated charge-discharge cycles accumulate continuously, eventually leading to local short circuits or interface failure. The PVDF support layer, by providing a flexible yet robust mechanical framework, ensures the structural integrity of the composite membrane throughout the battery's entire life cycle and serves as a crucial bridge connecting material-level performance and battery-level reliability.

[0215] The process parameter optimization experiments (Examples 2-11) systematically revealed the robustness and parameter tolerance range of the technology of this application. The following examples are used to illustrate the parameter variation trend and are not intended to obtain optimal performance.

[0216] Regarding the electric field gradient, the final value increased from 0.4 V / cm (Example 2) to 1.0 V / cm (Example 3), and σ⊥ increased from 1.5 × 10⁻⁶. -3 Up to 3.5×10 -3 The S / cm ratio showed a monotonically increasing trend, and the A value also increased from 2.3 to 3.7, indicating that a stronger gradient final value did indeed drive a higher degree of orientation. The conductivity of Example 3 (final value 1.0 V / cm) was even slightly higher than that of Example 1 (final value 0.8 V / cm), while the current density was still controlled at 0.5 mA / cm. 2 The following indicates that there is still some room for improvement within the process safety boundary. Combining the data from Examples 1, 2, and 3, the final gradient value of 0.5V / cm to 1.0V / cm is the effective operating range, and the optimal balance between performance and process safety can be obtained near 0.8V / cm.

[0217] The effect of preparation temperature on performance exhibits an inverted U-shaped trend. The σ⊥ values ​​at 60℃ (Example 4) and 80℃ (Example 5) are 2.2 × 10⁻⁶ and 2.2 × 10⁻⁶, respectively. -3 S / cm and 2.5×10 -3 S / cm, all reached 2×10 -3 The threshold requirement for S / cm is 3.2 × 10⁻⁶, but below 70°C (Example 1). -3 S / cm. At excessively low temperatures, crystallization kinetics slow down, and the MOF crystal fails to grow and oriented sufficiently within the electric field's duration. At excessively high temperatures, solvent evaporation is too rapid, compressing the crystal growth window and potentially introducing voids and internal stress defects. Data from Examples 4 and 5 support the layered description of the electric field-induced directional casting temperature as "60℃~80℃" and "65℃~75℃" in this application.

[0218] The effect of solvent composition also exhibits a clear regularity. Under the conditions of DMF:ACN=1:1 (Example 6) and 3:1 (Example 7), σ⊥ is 2.0×10⁻⁶. -3 S / cm and 2.8×10 -3 S / cm. When the ACN ratio increases (Example 6), the solvent evaporation rate accelerates, the crystal growth time shortens, and the orientation adequacy decreases (A=2.7 vs. 3.5 in Example 1). When the DMF ratio increases (Example 7), the increased solvent viscosity is beneficial for maintaining the crystal growth environment but may affect the electric field-driven migration efficiency. When the DMF:ACN ratio is 2:1 (Example 1), the optimal balance between evaporation rate and crystallization kinetics is achieved.

[0219] The exploration of parameters related to MOF film thickness and LLZO layer thickness revealed a trade-off between structure and performance. When the MOF layer was as thin as 5 μm (Example 8), σ⊥ actually increased to 3.8 × 10⁻⁶. -3 S / cm (thin-layer bulk impedance is lower), but the interfacial impedance does not change significantly (22Ω·cm). 2 Thin films face pinhole risks and mechanical integrity issues in practical applications. When the MOF layer thickness is increased to 15 μm (Example 9), σ⊥ decreases to 2.2 × 10⁻⁶. -3 The increase in bulk resistance (S / cm) partially offset the conductivity advantage of the orientation channels. The LLZO layer was increased from 50 nm (Example 10) to 150 nm (Example 11), and the Rint was increased from 18 to 48 Ω·cm. 2 This presents a competitive relationship between enhanced protection and increased transmission impedance. The 50nm LLZO layer has the lowest interface impedance but a smaller protection margin, while the 150nm layer provides sufficient protection but introduces a significant impedance penalty. The optimal balance between protection and transmission efficiency is achieved in the 70nm~100nm range.

[0220] Multi-parameter collaborative optimization Example 12 achieved further performance improvements within a process framework close to Example 1 by fine-tuning the temperature to 72℃, increasing the MOF layer thickness to 12μm, adjusting the LLZO layer thickness to 80nm, and increasing the PVDF layer thickness to 20μm: σ⊥ reached 3.8×10 -3 S / cm, A value 3.8, Rint drops to 20 Ω·cm 2 The Li-symmetric cell achieved a stable time exceeding 550 hours and a capacity retention rate of 93.5% after 200 cycles. The overall performance of Example 12 is significantly better than that of Example 1, demonstrating a positive synergistic effect between various process parameters and showcasing that there is still room for further optimization and improvement of this technology.

[0221] Material substitution experiments verified the versatility of the technical solution presented in this application. Example 13 used a Zr-phosphonate lithium framework to replace Li-HPPO, achieving a σ⊥ of 2.5 × 10⁻⁶. -3 The S / cm, A value of 3.1, and Eox of 4.6V, although lower than those of the Li-HPPO system, still meet the core performance threshold, proving that this application is not limited to Li-HPPO as a single material. The gradient electric field-induced directional growth technique has good applicability to all phosphate / phosphonic acid anchored MOFs of the same group. Example 14 uses LLZTO instead of LLZO as the ceramic interface layer, with σ⊥ of 3.0 × 10⁻⁶. -3 S / cm, Rint is 28Ω·cm 2 The Li symmetric cell had a stability time of 480 hours, and its performance was basically the same as that of Example 1, indicating that the ceramic interface layer material is replaceable and expands the flexibility of the technical solution.

[0222] Example 15, a high-voltage cathode verification example, extends the test platform from NCM811 to LMNO (~4.7V). With the exact same electrolyte structure as in Example 1, Eox reaches 4.8V, providing ample safety margin for the high-voltage operating range of LMNO. Example 15 achieves 88.5% capacity retention and 72.0% 2C rate retention after 200 cycles in the LMNO system, directly verifying the high-voltage adaptability of the composite electrolyte in this application and providing experimental evidence for cathode matching in next-generation high-energy-density solid-state batteries.

[0223] Based on all test data, the electric field-induced directional growth MOF composite solid electrolyte of this application exhibits comprehensive performance advantages. In terms of ion conduction, the room temperature σ⊥ reaches 3.2 × 10⁻⁶. -3 S / cm (based on Example 1), after co-optimization, can reach 3.8 × 10⁻⁶. -3The S / cm (Example 12) achieved an improvement of approximately 9 times compared to the no-field control, and the high anisotropy of the A value of 3.5~3.8 directly proves the successful construction of the through-type oriented channel. Regarding interface properties, the LLZO ceramic layer reduced the interface impedance to 25 Ω·cm. 2 The Li-symmetric cell exhibits a stable time exceeding 500 hours, effectively suppressing lithium dendrite growth. Regarding electrochemical stability, the 4.8V oxidation decomposition potential meets the wide voltage matching requirements for cathodes ranging from NCM811 to LMNO. In terms of mechanical properties, a tensile strength of 12.5MPa and an elongation at break of 15.2% ensure the structural integrity of the electrolyte membrane throughout the entire battery assembly and service life.

[0224] More importantly, through systematic comparative experiments, this application clearly demonstrates the necessity and irreplaceability of each core technological innovation. Gradient electric field-induced directional growth (verified in Comparative Examples 1 / 2 / 7), selection of phosphate-based MOF materials (verified in Comparative Example 5), LLZO interface enhancement (verified in Comparative Example 4), PVDF mechanical support (verified in Comparative Example 6), and the threshold effect of the electric field gradient (verified in Comparative Example 3)—these innovative elements are not simply superimposed, but rather form a multi-level synergistic effect of "orientation conduction + interface stability + mechanical integrity + electrochemical safety." Process parameter window experiments demonstrate that this technology can achieve effective performance within a wide parameter range, providing ample process tolerance for industrial applications. Material substitution and battery system expansion experiments prove the versatility and scalability of the technical solution. With the accelerated industrialization of solid-state batteries, the electric field-induced directional growth technology of this application is expected to provide a practical technical path for the large-scale preparation and high-performance application of MOF-based solid electrolytes.

[0225] Table 1-1

[0226]

[0227] Table 1-2

[0228]

[0229] In Tables 1-1 and 1-2, Example 1 and Comparative Examples 1 to 7 belong to the core innovation verification group, Example 2 to Example 11 belong to the process parameter window verification group, and Example 12 to Example 15 belong to the application expansion and collaborative optimization group.

[0230] Table 2-1

[0231]

[0232] Table 2-2

[0233]

[0234] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A battery cell, characterized in that, include: A battery cell assembly, wherein the battery cell assembly is formed by stacking or winding a positive electrode sheet, a solid electrolyte membrane, and a negative electrode sheet; A housing having a receiving space, within which the battery cell assembly is located; The solid electrolyte membrane includes a core conductive layer, an interface reinforcement layer, and a mechanical support layer, wherein the core conductive layer is made of a metal-organic framework material. The metal-organic framework material has one-dimensional channels, and the metal-organic framework material includes at least one of the following: lithium conductive framework with dihydrogen / monohydrophosphate bridging, derivatives of Zr / Ti-phosphonic acid rigid frameworks after lithiation treatment, and multi-anionic metal-phosphonic acid / phosphonate / phosphonic acid-carboxylic acid hybrid frameworks. The material of the interface reinforcement layer includes a ceramic electrolyte, and the material of the mechanical support layer includes a polymer; The preparation method of the metal-organic framework material includes: Preparation of metal-organic framework precursor solutions. The metal-organic framework precursor solution was subjected to directional casting under a protective atmosphere at 60°C to 80°C by electric field induction to obtain the metal-organic framework material. In the electric field-induced directional casting process, the electric field strength is controlled to increase from a first electric field strength to a second electric field strength within 3 to 6 hours. The first electric field strength is 0.05 V / cm to 0.1 V / cm, and the second electric field strength is 0.8 V / cm to 10 V / cm. The rate of increase of the electric field strength is 0.12 (V / cm)·h. -1 ~0.23 (V / cm)·h -1 , The solid electrolyte membrane has an orientation degree of 0.7 or higher and a room temperature ionic conductivity of 2 × 10⁻⁶. -3 S / cm or higher.

2. The battery cell according to claim 1, characterized in that, The diameter of the one-dimensional channel is 0.6 nm to 1.2 nm, and the pore volume is 0.1 cm. 3 / g~0.8cm 3 / g, BET specific surface area is 50cm² 2 / g~800cm 2 / g.

3. The battery cell according to claim 1, characterized in that, The molecular formula of the lithium conductive framework containing dihydrogen / monohydrophosphate bridging is Li3(H2PO4)(HPO4)2.

4. A method for preparing a single battery cell, characterized in that, include: A battery cell assembly is provided, wherein the battery cell assembly is formed by stacking or winding a positive electrode sheet, a solid electrolyte membrane, and a negative electrode sheet; A housing is provided to house the battery cell assembly within the housing; Perform the formation step; The solid electrolyte membrane includes a core conductive layer, an interface reinforcement layer, and a mechanical support layer, wherein the core conductive layer is made of a metal-organic framework material. The metal-organic framework material has one-dimensional channels, and the metal-organic framework material includes at least one of the following: lithium conductive framework with dihydrogen / monohydrophosphate bridging, derivatives of Zr / Ti-phosphonic acid rigid frameworks after lithiation treatment, and multi-anionic metal-phosphonic acid / phosphonate / phosphonic acid-carboxylic acid hybrid frameworks. The material of the interface reinforcement layer includes a ceramic electrolyte, and the material of the mechanical support layer includes a polymer; The preparation method of the metal-organic framework material includes: Preparation of metal-organic framework precursor solutions. The metal-organic framework precursor solution was subjected to directional casting under a protective atmosphere at 60°C to 80°C by electric field induction to obtain the metal-organic framework material. In the electric field-induced directional casting process, the electric field strength is controlled to increase from a first electric field strength to a second electric field strength within 3 to 6 hours. The first electric field strength is 0.05 V / cm to 0.1 V / cm, and the second electric field strength is 0.8 V / cm to 10 V / cm. The rate of increase of the electric field strength is 0.12 (V / cm)·h. -1 ~0.23 (V / cm)·h -1 , The solid electrolyte membrane has an orientation degree of 0.7 or higher and a room temperature ionic conductivity of 2 × 10⁻⁶. -3 S / cm or higher.

5. The method for preparing a single battery cell according to claim 4, characterized in that, The method for preparing the interface enhancement layer includes: The interface enhancement layer is formed by sputtering deposition on the surface of the core conductive layer.

6. The method for preparing a battery cell according to claim 5, characterized in that, In the sputtering deposition, the working gas pressure is controlled at 0.1 Pa to 1 Pa, the sputtering power is controlled at 100 W to 500 W, the substrate temperature is controlled at room temperature to 80 °C, and the deposition rate is controlled at 0.05 nm / s to 0.5 nm / s.

7. The method for preparing a single battery cell according to claim 4, characterized in that, The preparation method of the mechanical support layer includes one of solution casting composite and hot pressing composite.

8. The method for preparing a battery cell according to claim 7, characterized in that, The solution casting composite method includes: The polymer is dissolved in an organic solvent to form a casting solution; After the casting liquid is spread on the surface of the interface reinforcement layer, the organic solvent is evaporated at 80℃~120℃ to obtain the mechanical support layer.

9. The method for preparing a battery cell according to claim 7, characterized in that, The hot-pressing composite method includes: Preparation of polymer preforms; The polymer preform is hot-pressed at 60°C to 120°C to obtain the mechanical support layer.

10. A battery device, characterized in that, The battery device includes one or more of the following: battery cell as described in any one of claims 1 to 3, or battery cell prepared by any one of claims 4 to 9.

11. An electrical appliance, characterized in that, The electrical device includes the battery device as described in claim 10, the battery device being used to provide electrical energy.

12. An energy storage device, characterized in that, The energy storage device includes the battery device as described in claim 10, the battery device being used to store electrical energy.

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